Known methods for adjusting bank note processing machines wherein threshold values of sensors are defined for recognizing bank notes unfit for circulation require an operator to select and define suitable threshold values for the sensors. The threshold values defined by the operator then serve to separate the bank notes to be processed into bank notes fit for circulation and those unfit for circulation by means of the bank note processing machine, for which purpose the bank notes are sorted by the bank note processing machine into different output pockets for example.
The disadvantage of known methods is primarily that it is very complicated and laborious for the operator to define suitable threshold values for the sensors of the bank note processing machine. He starts out for example from threshold values already given by the manufacturer of the bank note processing machine, which are firmly set. Problems arise e.g. from aging or soiling of the bank note processing machine or from changes in the bank notes to be processed. If one or more of the threshold values are defined only slightly too high by the operator, bank notes that are actually no longer fit for circulation are classified by the bank note processing machine as fit for circulation. However, if one or more of the threshold values are defined only slightly too low by the operator, bank notes that are actually fit for circulation are classified by the bank note processing machine as no longer fit for circulation. Thus the bank notes to be processed are not separated into bank notes fit for circulation and those unfit for circulation in the way desired by the operator.